1. Technical Field
The present invention relates to information storage devices, and more particularly, to information storage devices using magnetic domain wall motion and methods of operating the same.
2. Description of the Related Art
Examples of conventional nonvolatile information storage devices in which recorded information is retained even when power is cut-off include hard disk drives (HDDS) and nonvolatile random access memories (RAMs).
Conventional HDDs use a rotating part to store information. However, the rotating part may wear down over time, thereby increasing the likelihood of operational failure and thus reducing reliability.
An example of a conventional non-volatile RAM is a flash memory. Although the flash memory does not use a rotating part, it has relatively slow reading and writing speeds, a relatively short life span, and a relatively small storage capacity when compared to a conventional HDD. Flash memories may also have relatively high manufacturing costs.
Another conventional information storage device uses the principle of magnetic domain wall motion of a magnetic material. In these conventional magnetic information storage devices, a minute magnetic region that constitutes a ferromagnetic substance is referred to as a magnetic domain. A boundary portion between magnetic domains having different magnetization directions is referred to as a magnetic domain wall. The magnetic domains and the magnetic domain walls may be moved by applying current to a magnetic layer.
However, the information storage device using the magnetic domain wall motion is still in an initial stage of development and some problems still need to be resolved before it can be practically used. In particular, an improved information recording method is required to enable practical use of information storage devices using magnetic domain wall motion.